Hygrothermograph



FIG. 1 is a first perspective view of a hygrothermograph showing the new design;

FIG. 2 is a second perspective view of the hygrothermograph showing the new design;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a left view thereof;

FIG. 6 is a right view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof. 

CLAIM The ornamental design for a hygrothermograph, as shown and described. 